Dewar bottle valve lockout cover

ABSTRACT

A lockout cover for restricting access to ports, valves, regulators and/or gauges shielded by a halo handling ring on top of a Dewar bottle. The lockout cover includes a cap seatable on the halo ring. A hatch on a side of the cap can be pivoted between an open position to allow access to the ports, valves, regulators and gauges, and a closed position to allow locking the cap to the halo ring to block access to the ports, valves, regulators and gauges.

TECHNICAL FIELD

The present invention relates generally to cryogenic fluid containers and more specifically to valve covers for Dewar bottles.

BACKGROUND ART

A vacuum flask or “Dewar” bottle is a vessel which maintains its contents cold (or hot) with an evacuated space insulating the contents from the environment. Vacuum flasks are used in laboratories and factories to store liquids such as oxygen and nitrogen which become gaseous at well below ambient temperature. The Dewar flask's excellent insulation keeps the contents liquid for a long time without the need for expensive refrigeration equipment, but heat leaking into the extremely cold interior of the bottle slowly boils off the liquid so that a stoppered opening protected by a pressure relief valve is necessary to prevent pressure from building up and shattering the flask. U.S. Pat. No. 872,795 titled “Double Walled Vessel with a Space for a Vacuum between the Walls” was granted to R. Burger on Dec. 3, 1907.

FIG. 1 is a perspective view of a conventional Dewar bottle 10. The bottle 10 may be spherical, lozenge shaped, or, as shown, cylindrical, and has a circumferential dimension 12 which has a center point 14 and defines a plane. A longitudinal (and as illustrated, vertical) axis 16 passes perpendicularly through the plane at its center point 14. The bottle has a top or engagement end 18 having a central opening (not visible) holding a manifold 20 with a center hole (not visible) through which is lowered a float rod (not visible) for measuring the volume of cryogenic liquid contained within the bottle. Depending on the amount of liquid in the bottle, the float rod moves up and down and indicates its elevation on a liquid level gauge 22. A gauge protector 24 on top of the gauge protects the upper end of the float rod. The manifold 20 also has for example as shown four (or up to six) radial ports for receiving valves and/or regulators. A liquid valve 26 can be opened to deliver the cryogenic contents of the bottle in liquid form. A gas valve 28 can be opened to deliver the cryogenic contents of the bottle in gaseous form. A pressure relief valve 30 allows manual release of pressure, and a vent valve 32 automatically releases excess pressure from the bottle when its contents expands due to heat leaking in. A pressure builder valve 34 is used. Pump out caps 36 and 38 cover tank utility openings. A number of handling posts 40 rise from to top 18 of the bottle to support a handling or “halo” ring 44, which serves as a guard rail surrounding and partially protecting the cluster of valves, and providing a handle by which the bottle may be picked up.

A problem with Dewar bottles in use, particularly outdoors or in other places open to the public, is that the valves and regulators are accessible to unauthorized persons who may adjust or tamper with the valves or regulators. This can interfere with the intended application of the Dewar bottle. Further, cryogenic liquids stored in Dewar bottles are extremely cold, at least around minus 300 degrees F., and their vapors can rapidly freeze human tissue and can cause many common materials such as carbon steel, rubber, and plastics to become brittle or even break under stress. All cryogenic liquids produce large volumes of gas when they vaporize. Even in well-insulated containers cryogenic liquids cannot be maintained in their liquid state indefinitely and, if vaporized in a sealed container, will produce enormous pressures that could explode the container.

U.S. Pat. No. 6,119,718 discloses a cylinder valve safety cover. It is designed to protect a valve possibly on a compressed gas cylinder and it can be locked, but is not intended for a cryogenic Dewar bottle as it would not fit on a tank with a halo ring, and is not very secure as it is made of plastic. U.S. Pat. Nos. 4,678,003; 5,058,758; 5,638,858; 5,845,809; 6,209,749; and 6,247,491 disclose covers for compressed gas cylinder valves but they cannot be locked and do not fit on cryogenic Dewar bottles.

There is, therefore, a need for protecting Dewar bottle valves and regulators from damage and/or unauthorized access.

SUMMARY

The present invention provides a lockout cover for restricting access to ports, valves, regulators and/or gauges shielded by a halo handling ring on top of a Dewar bottle. The lockout cover includes a cap comprising, in a preferred embodiment, a cylindrical wall and a planar lid. The lid has an inside surface on opposite sides of which two pairs of seating hooks face a gap in the wall. The cover is positioned over a Dewar bottle and the pairs of hooks are seated against the halo handling ring. The cap, except for the gap in the wall, covers any valves and regulators on the Dewar bottle. The gap can be closed by a catch box that is hinged to the lid. The catch box has slots which line up with slots in tabs on the wall to accept a locking bolt. The catch box is pivoted to its closed position and the bolt is inserted through the slots in the box and wall tabs. A padlock, for example, is then used to lock the bolt in the catch box to block adjusting, tampering with or stealing the valves or regulators. Only authorized personnel having a key will be able to unlock the box and access the valves and regulators.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art Dewar bottle having on top several valves and a halo ring which partially protects the valves and serves as a handle.

FIG. 2 is a perspective view of a lockout cover according to a preferred embodiment of the invention, closed on top of a Dewar bottle.

FIG. 3 is a perspective view from beneath of an opened lockout cover according to a preferred embodiment of the invention.

FIG. 4 is a perspective view from above of the opened lockout cover of FIG. 3.

FIG. 5 is a cutaway side elevation view of an opened lockout cover engaged but not locked on the top of a Dewar bottle, omitting gauges, valves, regulators and venting perforations for clarity's sake.

FIG. 6 is a partially cutaway perspective view of the lockout cover engaged with and closed on the top of a Dewar bottle.

FIG. 7 is a side elevation view of a lockout cover engaged, closed and locked onto the top of a Dewar bottle.

DETAILED DESCRIPTION

FIG. 2 shows a valve lockout cover 100 according to a preferred embodiment of the invention, mounted on a Dewar bottle 10. Cover 100 includes a cap 102 which, in a preferred embodiment, is formed by a cylindrical wall member 104 and a planar lid member 106. The parts of cover 100 are preferably made of aluminum or another metal. Wall member 104 and lid member 106 may be riveted, spot welded, or otherwise joined together. A catch box or hatch 108 is attached by a hinge 110 to lid 106. Catch box 108 can be opened or closed to allow or block access to valves, regulators, and ports on the Dewar bottle as explained below. Lid 106 preferably has a center hole 112 to accommodate a protruding gauge protector 24 as is visible in FIG. 7. Alternatively, if bottle 10 did not have a gauge protector higher that the halo ring 44, or if the lid were enough higher in its center, hole 112 could be dispensed with. Wall 104 preferably has perforations 114 to disperse gas which may be released by vent valve 32 rather than risk flammable or toxic gas accumulating inside the cover.

As can be seen in the bottom view of FIG. 3, cylindrical wall 104 is open in an arc between wall ends 116 and 118, which have respective outward turned tabs 120 and 122. Tabs 120 and 122, which may be integral with wall 104 or discrete pieces attached to the wall ends, have slots 124 and 126 respectively. Catch box 108 has a side panel 128 with a slot 134 corresponding to tab slot 124, and a side panel 130 with a slot 136 corresponding to tab slot 126.

On the inside of cap 102, visible in FIG. 3, lid 106 has seating means including a pair of hooks 140 positioned opposite the arc between wall ends 116 and 118. Alternately, the seating means could be formed by a single hook. Optionally, the seating means may also include abutments such as that shown at 142 spaced around wall 104, and an additional hook or pair of hooks 144 positioned in the arc between wall ends 116 and 118. The hooks 140, 144 are sized to leave enough space between the base of the hooks on the surface of the lid 106 and the lip of the hooks to seat a halo ring 44 (see FIGS. 5 and 6).

A catch 150 is mounted on the underside of the top of catch box 108. When catch box 108 is pivoted to its closed position, slots 124, 134, 126, and 136 line up and the distal end of catch 150 extends under and around the halo ring 44 to meet or nearly meet the inner side of lid 106 and hold the cap 102 on the halo ring. The bottom panel 160 of catch box 108 has an edge 162 which may be scalloped out as shown to leave enough space between edge 162 and the surface of bottle 10 to thread a supply hose from a valve inside cover 100 to the outside environment. In other embodiments, a hose or hoses could be threaded through holes provided elsewhere in cover 100. If it is not necessary to thread a hose out under box 108 then side panels 128 and 130 could be much closer together. Other embodiments could even eliminate catch box 108 and replace it with a pivoted catch having a lock slot suitable to cooperate with slots 124 and 126 of the wall tabs 120 and 122.

Cover 100 also includes a bolt 200 which has a head 202, a shaft 204, and a tip with a hole 206. When catch box 108 is closed to line up slots 124, 134, 126, and 136, the bolt 200 can be inserted through the slots until the head rests on the outer side of the tab where the tip entered and the tip itself sticks out beyond the last tab. The tabs with slots 124, 126, the panels with slots 134, 136, and the bolt 200 together facilitate locking the catch 150 in the closed position.

FIG. 4 is an alternate perspective view from above of the lockout cover in the open position as in FIG. 3, illustrating how the only movable parts accessible from the outside of the cover are bolt 200 (and a padlock 210 which would be out of sight behind catch box 108).

FIG. 5 is a side elevation view of a bottle 10 and cover 100, cut away along a vertical plane passing through bottle axis 16 and catch 150, showing how the opened lockout cover fits over and is engaged with a halo ring on a Dewar bottle. The distance “T” between the end of hook 144 and a vertical plane through hinge 110 is sufficient to allow the cover to be lowered over the horizontal thickness of a halo ring 44. The distance “D” between the concave faces of hooks 140 and 144 where they meet the inner side of lid 106 is substantially equal to the diameter of the halo ring from the inside of the ring on the left to the outside of the ring on the right as shown, so that once the cover has been lowered over a halo ring the cover can be slid leftward as shown in FIG. 5 and the hooks 140 and 144 will securely seat the ring. The outside diameter “O” of the cylindrical wall 104 preferably does not exceed the horizontal diameter of Dewar bottles 10 that the cover 100 is used with.

FIG. 6 is a partially cutaway perspective view of a lockout cover 100 having seating hooks 144 engaged with the halo ring 44 on the top of a Dewar bottle 10, and catch box 108 closed.

FIG. 7 is a side elevation view of a lockout cover 100 engaged and closed on the top of a Dewar bottle 10. Cover 100 is held shut by inserting the shackle of a padlock 210 through the hole in the tip 206 of the bolt 200, and locking the padlock. The distal end of catch 150 approaches close enough to the inner side of lid 106 to capture the halo ring 44 and prevent removal of cover 100 from bottle 10.

When cover 100 has been positioned and locked on a Dewar bottle 10, if authorized technicians need to read a gauge(s) (not shown) connected to one of the valves on the bottle and extending beyond the halo ring 44 to inside catch box 108, then they may unlock padlock 210, remove bolt 200, and pivot catch box 108 up out of the way to allow access to the gauge, without having to remove cover 100 from the bottle.

The foregoing specification describes the present invention with reference to a specific embodiment. It will, however, be evident to a skilled artisan that various modifications and changes can be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. For example, a cover in another embodiment could include a cap formed differently; for example the two piece wall and lid combination could be replaced by a single dome-shaped member. Moreover, a skilled artisan, upon reading the disclosure, will readily envision other shapes possessing the same or similar advantages for the cap. Although perforations in the cap are shown as circular, other shapes such as slits may be suitable as well. Also, in addition to the metallic caps discussed herein, a skilled artisan will recognize that other materials may be utilized for fabricating various components or the entire cap. Such materials include, for example, High Density Polyethylene (HDPE) plastics, acetal plastics, and Ultra High Molecular Weight (UHMW) polymers. These and various other embodiments and techniques are all within the scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. 

1. A cover for a Dewar bottle having a halo ring mounted above a port on top of the bottle, comprising: cap means seatable on the halo ring to block access to the port; and lockable closure means for holding the cap means on the halo ring.
 2. A cover for a Dewar bottle having a circumferential dimension centered on a perpendicular axis, and an end with a handle ring centered on the axis, the cover comprising: cap means having an inner side and an outer side; catch means pivotally attached to the cap means for rotating from an open position to a closed position where the catch means prevents removal of the cap means from the handle ring; and locking means to facilitate locking the catch means in the closed position.
 3. The cover of claim 2 wherein the cap means comprises: a cylindrical wall member and a planar lid member.
 4. The cover of claim 3 further comprising seating means on the inner side for limiting movement of the cap means relative to the handle ring.
 5. The cover of claim 4 wherein the seating means comprises at least one hook.
 6. The cover of claim 5 wherein the seating means comprises at least one pair of hooks.
 7. The cover of claim 5 wherein the seating means comprises at least one abutment.
 8. The cover of claim 3 wherein: the cylindrical wall member has wall ends with outward turned tabs separated by a gap; the catch means comprises a catch box having side panels spaced apart by a distance similar to the width of the gap; and the locking means comprises slots in each of the tabs and side panels that line up when the catch box is rotated to a closed position, and a bolt having a head, a shaft that slides through the slots, and a shaft tip with a hole.
 9. The cover of claim 8 wherein the catch box has a bottom panel with a scalloped recess to permit passage of a hose.
 10. The cover of claim 3 wherein the cylindrical wall member has perforations.
 11. A cover for a Dewar bottle having a handle ring protecting valves and ports, the cover comprising: a cap formed of a cylindrical wall and a lid, the cylindrical wall having a circumferential periphery surrounding the handle ring and the cap covering the controls and ports; a catch box giving access to a valve or port, pivotally mounted to a peripheral region of the cap and having an open position and a closed position, the catch box having a hook engaging the handle ring in the closed position; and locking means for holding the catch box in the closed position to secure the valve or port. 